IN ONE ASPECT, THE INVENTION RELATES TO COMPOUNDS HAVING THE FORMULA: WHERE R1-R6, A, B, Z, AND X ARE AS DEFINED IN THE SPECIFICATION, OR A PHARMACEUTICALLY ACCEPTABLE SALT THEREOF. THESE COMPOUNDS HAVE NEPRILYSIN INHIBITION ACTIVITY. IN ANOTHER ASPECT, THE INVENTION RELATES TO PHARMACEUTICAL COMPOSITIONS COMPRISING SUCH COMPOUNDS; METHODS OF USING SUCH COMPOUNDS; AND PROCESSES AND INTERMEDIATES FOR PREPARING SUCH COMPOUNDS.